Thrust bearing systems for counter-rotating propeller shafts for ships' propellers are known from FIGS. 19 and 20 of the publication "HANSA - Schiffahrt - Schiffbau - Hafen", volume 109, No. 14, 1972, page 1285. Counter-rotating ships, propeller shafts are also known from the German Auslegeschrift No. 1,272,157 and the German Auslegeschrift No. 1,905,921. Axial thrust bearings, each with a plurality of friction bearing elements between annular friction bearing surfaces for ships, propeller shafts are known from the German Offenlegungsschrift No. 2,409,242 and the German Utility Patent No. 6,916,569.